Tag Archives: soil erosion

Human-induced erosion could make some soils around the world unfarmable by the end of the century

Human-induced soil erosion is a serious threat to global sustainability, endangering global food security, driving desertification and biodiversity loss, and degrading other vital ecosystem services, researchers say. According to a new study, erosion is affecting the longevity of the soils across the world.

Credit Flickr Fabian Schmidt

Soils have underpinned the health and longevity of every society. They are a critical global resource, providing the basis of food production and storing and filtering our water resources. Soils also represent the largest organic carbon store and a platform for economic development. But pressures on the soil resource grow as food demands rise and land degradation increases.

To date, 36% of the world’s cultivable land has been farmed and in many areas of the world, conventional plow-based agriculture is accelerating local soil degradation. The UN estimates that 66% of the world’s soils suffer from some form of degradation. Human-induced erosion is estimated to outpace soil formation, which means we now have thinner soils.

“Our soils are critically important and we rely on them in many ways, not least to grow our food”, said lead author Dan Evans in a statement. “There have been many headlines in recent years suggesting that the world’s topsoil could be gone in 60 years, but these claims have not been supported with evidence. This study provides the first evidence-backed, globally relevant estimates of soil lifespans.”

A study by Lancaster University in collaboration with researchers from Chang’an University in China, and KU Leuven in Belgium, looked at soil erosion data from around the globe, spanning 255 locations across 38 countries on six continents. They calculated the time it would take for the top 30 cm of soil to erode at each location—the soil lifespan.

They focused on that top layer of the soil as it’s usually rich in nutrients and organic matter, making it important for growing fibers, food, feedstock, and fuel. In their study, they included soils that are conventionally farmed as well as those managed with soil conservation techniques. That way they can see how changes to land-use practices can alter the lifespan of soil

The findings showed that 90% of the soils conventionally farmed around the world were thinning, with 16% having a lifespan of less than a century. At these sites, soil erosion is a significant threat to the soil’s capacity to grow food, support ecosystems, store and regulate water, cycle carbon and nutrients, and thus to the overall functioning of the soil system.

But there were reasons to be optimistic. The study showed soils managed with conservation strategies had a longer lifespan, promoting soil thickening. Only 7% of the conservation plot dataset had lifespans of less than 100 years, with nearly half exceeding 5,000 years and 39% exceeding 10,000 years

“Soil is a precious resource and we can’t afford to lose that much over a human lifetime,” said co-author Jess Davies in a statement. “We have the tools and practices to make a difference—employing the appropriate conservation methods in the right place can really help protect and enhance our soil resource and the future of food and farming.”

The researchers suggested using a set of strategies to extend soil lifespans and promoting annual soil gain, such as conservation and zero till practices, contour cultivation and terracing. These extend soil lifespans and may promote soil thickening, increasing the potential for water, carbon and nutrient storage, and thereby soil conditions.

The study was published in the journal Environmental Research Letters.

Peak oil – reached. Peak water – reached. Next on the list? Peak soil

Soil is becoming endangered – this is the reality a meeting between experts in Reykjavik has reached. They explain that this has to receive public awareness if we want to feed 9 billion by 2050.

Soil degradation is life degradation

 

soilThe main culprit is the one also responsible for global warming: Carbon.

“Keeping and putting carbon in its rightful place needs to be the mantra for humanity if we want to continue to eat, drink and combat global warming, concluded 200 researchers from more than 30 countries”.

Indeed, for all the attention the air and water gets, soil seems to be the forgotten child, just because we don’t eat or drink it. But everything we eat comes from it.

“While soil is invisible to most people it provides an estimated 1.5 to 13 trillion dollars in ecosystem services annually,” Glover said at the Soil Carbon Sequestration conference that ended this week.

It’s practically impossible to calculate the benefits that soil brings us – a mere cup of soil contains some 500.000 species, including worms, ants, fungi, bacteria and other microorganisms. 99% of our food comes from it, directly or indirectly, compared to the only 1% we get from oceans.

Soilcleans water, keeps contaminants out of streams and lakes, and prevents flooding; it can also absord massive quantities of carbon. But as hard as it may seem – it’s really fragile.

“It takes half a millennia to build two centimetres of living soil and only seconds to destroy it,” Glover said.

Plowing, removal of crop residues after harvest, and overgrazing all leave soil naked and vulnerable to wind and rain, resulting in gradual, often unnoticed erosion of soil. Erosion not only destroys crops, causes landslides and other catastrophes, but also releases carbon into the air.

“Soil can be a safe place where huge amounts of carbon from the atmosphere could be sequestered,” said Rattan Lal of Ohio State University.

So we’ve pretty much screwed the atmosphere – unless practically all of science that we do now is wrong, that’s a fact. We’re well into doing the same to the water, as a massive, large scale water shortage seems like a matter of time. Are we going to do the same with soil? Are we going to try to milk the cow until it runs totally dry? We know what should be done, we have the technology, and we also have the money for it.

A sad example

OLYMPUS DIGITAL CAMERA

About 1000 years ago, when the first settlers arrived there, Iceland was mostly covered by forests, lush meadows and wetlands. By the late 1800s, about 96 percent of all icelandic forrests were gone. Half of the grasslands were destroyed by overgrazing. Humans pushed the land way beyond the limit of sustainability, up to the point where it became barren.

Due to necessity, Iceland pioneered a number of groundbreaking techniques in terms of soil protection, but the results in the past 100 years are moving extremely slowly.

“We’re still fighting overgrazing here,” Halldórsson said.

But the public is living in the urban areas, has forgot these troubles, and is not supporting land restoration anymore.

“The public isn’t supporting land restoration. We’ve forgotten that land is the foundation of life,” Halldórsson said.

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